CROPPING SYSTEMS, FERTILIZERS FOR CORN 221 



MANURES AND FERTILIZERS FOR CORN 



269. Manures. The profitable increase in corn 

 yields from adding stable or farm manures is almost 

 universal. Probably the chief reason for this is that the 

 manure supplies organic matter, which when in proper 

 condition may greatly influence the water content of the 

 soil. The value of this indirect effect is evidenced by the 

 fact that manure sometimes greatly increases the yield 

 of corn where commercial fertilizers produce no increase. 

 The by-products of the decomposition of manure also 

 render more available the plant-food constituents already 

 in the soil. 



The marked effect of manure on the yield of corn is 

 shown by results from the Ohio, Pennsylvania, and Illi- 

 nois Stations: 



TABLE 17. RESULTS FROM THE Onio, 1 PENNSYLVANIA, 2 AND 

 ILLINOIS 3 STATIONS SHOWING RESULTS WITH BARNYARD 

 MANURE ON YIELD OF CORN 



1 Ohio Agr. Exp. Sta. Circ., 104, p. 17. 



2 Penn. Agr. Exp. Sta. Bui., 190. 



3 Hopkins' " Soil Fertility and Permanent Agr.," p. 473. 



